1. Field of the Invention
The present invention relates to a dental matrix band, and more particularly to a matrix band having both a metal member and a plastic member.
2. Description of the Prior Art
Matrix bands are well known in the art and, to date, have either been made of all metal or all plastic. The metal matrix bands have typically been used almost exclusively until the development of light-cured posterior composite resins (plastic) fillings for bicuspid and molars that are cured by use of a fiber optic light source.
The formula for these light cured posterior composites was actively developed in the mid-1980's and continue to be modified today. These new posterior composites are specially formulated to resist wear from chewing. Previously developed composite resins (light cured or self cured) were not wear resistant enough to be placed in the back teeth (bicuspids and Molars) where fillings have to endure much more chewing pressure. Light cured posterior composites were developed as a replacement for silver amalgam fillings. They are more aesthetic than silver amalgam because they come in tooth matching colors. There has been some concern in dentistry about the mercury in silver amalgam fillings. The posterior composites contain no mercury.
For these reasons, there has been an increasing interest and use of composite resins in dentistry since the mid-1980's. Dentists want to see any new filling material have a "track record" before they fully accept and use the material. Recently published studies are concluding that these light cured posterior composites do stand up to the increased wear generated in the back teeth. Placing these types of fillings in teeth require difference procedures and skills than are required to place silver amalgam. Patients are showing more and more interest in these fillings primarily because of aesthetic considerations. There have been several instruments and devices that have come on the market in the last year that make placement of light cured posterior composites easier.
A plastic matrix band must be used to place this material because fiber optic light is used to cure it and plastic allows the light to reach the material while keeping it is the proper form in the cavity preparation. The problem with the all plastic matrix bands that are available today arises in the procedure of placing these around the tooth before filling the cavity. After the cavity is drilled out, many times only one side of the tooth is drilled away, and the other side of the tooth is intact and in contact with the adjacent tooth. The adjoining areas are called "contacts" or "contact points". The contacts between the teeth are usually very tight. To get proper form and marginal seal, the matrix band must be fitted around the whole tooth to be filled. The all plastic band can be very difficult to place between the tight contact point because the plastic band is very thin and extremely pliable. The band will usually tear or crumple up and will not slide through the contact point between the teeth. To get the plastic matrix band in place it is usually necessary to "wedge" the tooth. This entails pushing a small piece of wood or plastic that looks like a piece of toothpick between the teeth where the contact point is, thereby separating the teeth enough to allow the plastic band to slip between the contact point. Even with wedging, it is still sometimes difficult if not impossible to get all the plastic band in place. Pushing the wedge between the teeth is not comfortable for the patient and it takes valuable time to allow the teeth to separate. With the use of the wedge there is generally some bleeding of the gums which can contaminate the field of operation. Metal matrix bands are much easier to place between contacts because of their stiffness and very rarely require wedging.
The present invention addresses the problems associated with the prior art matrix bands and allows dentists to place light cured posterior composition resins more easily by giving them a more user friendly matrix band.